PURPOSE: To enlarge cavity clearance, and to obtain a molded form having no warpage and sink and having excellent appearance by moving either of a female mold or a male mold so that the pressure of a molten resin fed into a cavity reaches a pressure value within a specific range during the supply of the polypropylene molten resin.
CONSTITUTION: Either of a female mold or a male mold 3 is moved so that the pressure of a molten resin 8 fed into a cavity 6 reaches a value from 5kg/cm2 to 100kg/cm2 during the supply of the polypropylene molten resin 8, thus scaling up a cavity clearance. A skin layer is formed while applying pressure from 5kg/cm2 to 100kg/cm2 at the same time as the completion of the supply of the molten resin. The cavity clearance is further enlarged, a foamed core layer is formed, and a molded form 8' is cooled in a mold.
MATSUMOTO MASATO
USUI NOBUHIRO
MATSUBARA SHIGEYOSHI
